while this is possible… i am not sure to recommend this 😀
also make sure there is still some space on the partition to be converted.
root@debian9:/# btrfs-convert /dev/sdb6 create btrfs filesystem: blocksize: 4096 nodesize: 16384 features: extref, skinny-metadata (default) ERROR: unable to create initial ctree: No space left on device WARNING: an error occurred during conversion, filesystem is partially created but not finalized and not mountable
i was able to remount the partition and delete some files.
if there is space… transformation should work 😀
btrfs-convert /dev/sdb6 create btrfs filesystem: blocksize: 4096 nodesize: 16384 features: extref, skinny-metadata (default) creating ext2 image file creating btrfs metadatacopy inodes [o] [ 0/ 13]
so the once ext3 partition is now btrfs… wohoo! 😀
root@debian9:/# lsblk -fs NAME FSTYPE LABEL UUID MOUNTPOINT sdb6 btrfs ext3 bc584588-19fd-4a10-b880-25bbe3b95bfc
there will be a folder created:
root@debian9:~# ll /mnt/ext3_btrfs_converted/ext2_saved total 248M drwxr-xr-x 1 root root 10 Jul 7 17:03 . drwxr-xr-x 1 root root 98 Jul 7 17:03 .. -r-------- 1 root root 10G Jul 7 17:03 image
the image file is a backup of the prior ext3 partition.
you can reverse back to ext3 via:
btrfs-convert -r /dev/sdb6 rollback complete
all files still there…
root@debian9:~# ll /mnt/ext3 total 84K drwxr-xr-x 3 root root 4.0K Jul 7 17:03 . drwxr-xr-x 13 root root 4.0K Jul 7 17:03 .. drwx------ 2 root root 16K Jul 7 17:02 lost+found -rw-r--r-- 1 root root 50K Jun 28 17:01 Richard-Stallman.jpg -rw-r--r-- 1 root root 12 Jul 7 14:48 stuff.txt